新生儿呼吸窘迫综合症(Neonatal-Respiratory-Distress-Syndrome).ppt

单击此处编辑母版标题样式,单击此处编辑母版文本样式,第二级,第三级,第四级,第五级,*,Neonatal Respiratory Distress Syndrome,(NRDS),Hyaline membrane disease(HMD),Most common cause of respiratory failure in the first days in the premature infants,Reason is surfactant insufficient in lungs which lead to breathing failure and need the assistant ventilation,Occurring in 12%of newborn infants,increases by smaller GA:50%of GA 28w,less than 30%of 3236w),Surfactant,Keep the lung alveoli open,Start synthesis in GA 2428w by,lung type II alveolar cells,Increase in 2835w,but produce,adequate amounts after 35w,double in alveolar within 24h,after birth,to adult level after,37d of birth,half-life 1224h,Surfactant Composition,Phospholipid,(PL),90%(neutral 5%),Phosphatidyl,cholin,(PC,Lecithin)40,Phosphatidyl,glycerol(PG)5,Sphingonyeline,(S)2%,others,Protein 10,A,3035kDa,18,oligomer,D,43kDa,12 oligomer,B,8kDa,dimer,C,4kDa,dimer,Function of Pulmonary Surfactant,lower alveolar surface tension,reduces respiratory work,Maintain alveoli,inflation,and,functional residual capacity,Accelerate lung fluid absorption,reduce alveolar effusion,Pathogen Opsonization,alveolar macrophage activation,Effects:,increase oxygenation,ameliorate ventilation/perfusion,anti-inflammation,Etiology,Risk factors:,Caucasian or male babies,P,revious birth of baby with RDS,Cesarean delivery(more water in lung),P,erinatal asphyxia,M,ultiple births(multiple birth babies are often premature),I,nfants of diabetic mothers(too much insulin in a babys,system may delay surfactant production),Perinatal infection,B,abies with patent ductus arteriosus(PDA),Pathophysiology,Lack of surfactant in the lungs of infants,Avery and Mead,Am J Dis Child,1959,progressive atelectasis,loss of functional residual capacity(FRC),alteration of ventilation-perfusion ratio,Weak respiratory muscles and compliancy of chest wall,impair alveolar ventilation,Diminished oxygenation,cyanosis and acidosis,increased pulmonary vascular resistance(PVR),right-to-left shunting through ductus arteriovenous,intrapulmanary ventilation-perfusion mismatch,Etiology and,Pathophysiology,Pulmonary immaturity,results in surfactant,deficiency,Alveoli collapse at the,end of expiration leads to,respiratory failure,Surfactant deficiency,may arise after asphyxia,/shock and acidosis,alveolar surface tension is higher,Diminished PS,Pulmonary,atelectasis,Impaired gas exchange,(hypoxia and acidosis),Pulmonary artery hypertension,Rightto-left heart shunt,Pulmonary capillary permeability increase,Forming pulmonary hyaline membrane,Pathology,atelectasis,pulmonary edema,vascular congestion,hemorrhage,generalized capillary leak and mucosal necrosis leads to the smaller air filled terminal airways;the respiratory bronchioles and alveolar ducts are surrounded by collapsed alveoli filled with debris in a near uniform distribution(,hyaline membranes,),Clinical Presentation,Present at birth or first 2 to 6 h of birth:,respiratory difficulty that gets progressively worse,tachypnea(rapid breathing),cyanosis(blue coloring),with increasing oxygen requirements,chest retractions,nasal flaring,grunting sounds with breathing,Characterized by progressive worsening of cyanosis and dyspnea,symptoms usually peak on 2 to 3 day,and will recovery after 3 d,Diagnosis,Diagnosis can be decided by a combination of,assessments,including GA,a history of risk,factors,the signs,chest X-ray and blood gases.,Radiographic Changes of RDS,a bell shaped thorax with diffuse and symmetrical,“ground glass”,called,reticulogranular,pattern with,“air,bronchogram,”,or severe bilateral opacity and obliterate the cardiac border,“white-out lung”,Laboratory Findings,Mixed acidosis,Lecithin(L)/Sphingomyelin(S)0.6,PaO,2,50mmHg or TcSO,2,85%,Pressure:,410cm H,2,O,flow 5L/min,32,C,humidity 100%,Conventional Mechanical Ventilation(CMV),Indication:,PaO,2,50mmHg or TcSO,2,70mmHg;or frequent apnea,Complication:,PAL(pulmonary air leak),BPD(bronchopulmonary dysplasia;or CLD),Retinopathy of prematurity(ROP),VAP(ventilator-associated pneumonia),Application of Pulmonary Surfactant,Intratracheal instillation:50200mg/kg,612h interval,Neonatal Respiratory Distress Syndrome(NRDS),meconium aspiration syndrome(MAS),Pneumonic Respiratory failure,Acute lung injury,ARDS,Respiratory failure after open-chest surgery or lung transplantation,Prevention,Avoidance of,preterm birth:,most important,Careful maternal care and fetal monitoring,Accelerate fetal lung maturation,Maternal glucocorticoids,(betamethasone,examethasone,),24h before birth,Administration of a first dose of PS into the trachea of symptomatic premature infants immediately after birth or during the first 24hr of life,The most effective way to prevent RDS is to prevent preterm delivery.If preterm delivery is inevitable,attempts to“mature the fetus”are reasonable.,Question:,What is NRDS/HMD?,Which infants do not have adequate surfactant?,What are risk factors of NRDS?,What is the clinical course of NRDS?,How do you diagnose NRDS?,What are other causes of respiratory distress?,How do you manage or prevent NRDS?,Thank you!,